400602

Navigate to SINUMERIK HMI > Diagnosis > Spindle and document current NCK MD parameters: MD10040 (spindle type), MD10043 (max spindle speed), MD10050 (gear stage 1 upper limit), and MD10070 (spindle control type). Record exact values.

Do not modify parameters yet; document baseline only.

Access PLC program via STEP 7 or HMI service menu and verify DB4 spindle configuration block matches documented NCK parameters. Cross-reference spindle ID, gear ratios, and control mode flags in the PLC spindle structure.

If mismatch detected, update PLC DB4 spindle configuration to match NCK MD values. Recompile and download PLC program. Cycle control power OFF/ON (15 seconds minimum) to force full system initialization.

Ensure PLC download is complete before power cycle to prevent incomplete commissioning state.

Return to SINUMERIK HMI, perform 'Spindle Configuration Check' under Maintenance menu, and verify alarm 400602 clears. Document all parameter values in commissioning log.

In SINUMERIK HMI, navigate to Parameters > Machine Data > Spindle and review MD10000 (number of spindles), MD10050 (gear stage 1 upper limit), MD10051, MD10052, MD10053, MD10054 (subsequent gear limits). Note the number of active gear stages defined.

Compare documented gear stage count with PLC DB4 spindle data structure (typically found in OB 35 or spindle initialization block). Verify GEAR_STAGES variable matches the count in NCK MD parameters.

Gear stage configuration must be identical; even one missing stage triggers mismatch.

Correct the PLC DB4 structure to match NCK gear stage count and upper limit values (MD10050-MD10054). Recompile PLC program and download to control. Perform control power cycle (OFF 20 seconds minimum, then ON).

Test spindle gear selection via Manual mode: select each gear (G-code M3/M4 with S-value ranges corresponding to each stage). Confirm smooth transitions and verify alarm 400602 does not recur.

Verify system firmware versions: In SINUMERIK HMI, go to System Information and note NCK software version and PLC firmware version. Cross-reference both against Siemens compatibility matrix to confirm firmware compatibility.

Firmware mismatch (e.g., NCK 4.7.x with PLC 2.7.x) will cause configuration validation failures.

If versions mismatch, update both NCK and PLC to the same release level using official Siemens update procedure. If versions match, perform a complete PLC cold start: clear all PLC memory (SIEMENS START > Initialize > Delete All), then perform fresh download of entire PLC project.

Cold start erases all PLC data; back up custom PLC additions before execution.

After fresh download, monitor HMI System > Spindle Status during power-up sequence. Confirm spindle initialization completes without alarm 400602. If alarm persists, move to NCK diagnosis: run NCK trace (Diagnosis > NCK Debug) and capture spindle validation log.